Use the fields parameter

You may be able to improve performance by using the fields parameter on endpoint calls wherever possible and by limiting the amount of data you request from the server for each endpoint call to a specific set.

You should avoid using the default with endpoint calls, since that will fetch all fields. For example, if you use the default when calling the getCollections and listProducts endpoints, this would result in a large payload and longer server response time. Remember that you usually only need a subset of fields for the UI. For more information, see Understand widgets.